In article ,
"Arny Krueger" wrote:

Mark & Mary Ann Weiss wrote:
[snip]
Plus with a motor this large, the Xmax could be huge.

I don't believe that voice coils are the major issue when it
comes to Xmax. My informants tell me that its easy to make a
voice coil long, but its hard to provide a cone suspension
that is compliant enough to allow large excursions, while
holding the cone in the proper path with enough precision to
avoid mechanical damage while the cone is stroking. A larger
diameter voice coil vastly increases the weight of the
magnet assembly for a given amount of flux density.


Adire Audio used to have some discussions on high excursion subs before
they trashed their web site. They said that a major problem with high
excursions was that an oversized speaker surround would collapse or
invert itself from the air pressure. It would sound very bad and soon
tear.

Another problem is the area of the voice coil that is not in a magnetic
field. It does nothing but make heat. There's also terrible distortion
if the amount of the coil that is in the field doesn't remain constant
as the coil moves.

Adire can custom build a +/- 80mm excursion subwoofer motor called the
Parthenon for $3000. The cone/diaphragm is up to you.

I found a partial mirror of their old page:
http://www.acousticconcepts.com.au/Parthenon.html